A trajectory is a path in a two-dimensional workspace. A trajectory may be discretised or continuous and may result from a physical process, measurement of one or more parameters, or be entirely abstract. Sometimes it is necessary, for example when displaying an indication of measured data, to display a plurality of anti-parallel trajectories. In such situations, it is difficult to distinguish each of the plurality of trajectories due to, for example, the representations of the trajectories at least partially overlapping.
FIG. 1 shows twenty one simulated vehicle trajectories with each trajectory being represented by a piecewise-linear curve. The trajectories are formed by position measurements of each vehicle at periodic intervals with random errors included. A direction of motion is indicated by arrowheads superimposed at regular time intervals on each curve, the arrow heads providing an indication of time-dependant speed. However, one of the trajectories shown in FIG. 1 is for a vehicle heading in an opposing direction to the other vehicles.
It is difficult to individually resolve the overlapping trajectories, and to establish which trajectory is for the wrongly directed vehicle. One solution to this would be to represent each trajectory using thinner lines, and possibly also making the symbols smaller, but eventually the trajectories would become illegible and not convey the desired information.
It is an object of embodiments of the invention to at least mitigate one or more of the problems of the prior art.